Yeah that adds a lot more to the device, it turns into a PSP pretty much, except with the touch screen, which the PSP lacks. However, the adapter isn't too cheap at the moment, so prepare to pay ~$100 for it + the price of a DS to get full functionality out of your DS. There's some pretty good homebrew out for it right now, as well as emulators. And I think NDS rom backups work on it, if I'm not mistaken.